High density, long rod penetrators in the form of flechettes, pointed projectiles with vaned tails for stable flight, are utilized as anti-amour weapons, i.e. kinetic energy penetrators. Such kinetic energy (KE) penetrators are subcaliber and encased within a light weight aluminum alloy or composite material sabot that surrounds and builds out the diameter of the unit to allow it to be fired from the particular caliber weapon. The sabot is typically constructed in three segments; which segments are wrapped around the penetrator and typically held together by an obturator band located near the sabot's midsection, a bourrelet ring in the front and a tipping ring at the tail end of the sabot. The sabot has a windshield and a windshield tip in the front and at its back end a tail fin. The front bourrelet ring and the tipping tail end ring are both notched or otherwise weakened, or prestressed. Upon ignition of the propellant charge inside a cartridge case which holds the sabot—the KE projectile is propelled from the gun tube—the propulsion force being provided by a seal created between the sabot and the gun tube by the obturator ring. Upon exit from the muzzle of the gun tube, typically the sabot's front scoop catches the air rushing by the projectile and forces the sabot sections apart, such that the obturator band and retaining bands about the nose and tail of the sabot break, freeing the segments of the sabot to separate and fall away from the KE penetrator, such as a typical “Armor-Piercing Fin-Stabilized Discarding Sabot” or APFSDS. After the sabot sections are discarded, the KE penetrator continues to fly down range to impact the target with enough kinetic energy to defeat its intended target.
As stated above, sabots have traditionally been manufactured of light weight aluminum—wherein such a relatively light material provides increased muzzle velocity and correspondingly increased range and penetration by the subcaliber penetrator at the target. One example of such an aluminum APFSDS is the M900 105 mm sabot, which can be fired from the 105 MM M68 main gun on the M1 Abrams Tank or the Stryker Mobile Gun System. Another, example is the M829 APFSDS tank round designed for the 120 mm M256 main gun on the M1A1, M1A2 and M1A2 SEP Abrams main battle tank.
While aluminum is a relatively light weight metal, it is certainly heavy when compared to modern composite materials. However, while composite sabot structures have successfully been used in 120 MM smooth bore gun systems, where there is no spin, i.e. no significant torsional loads; the use of such composite materials in rifled gun systems has failed—composite sabot structures provide only a very low torsional load capability of about the order of 7000 inch-pounds and the spin effect from being fired from a rifled gun causes loss of the sabots body integrity (i.e. the sabots composite structure literally comes apart). To strengthen sabots for use in rifled gun systems, past attempts to introduce metal supports in the molding process have failed due to incompatibility of coefficient of expansion and contraction of the dissimilar composites and metal materials. Further, the obturator of a composite sabot is subjected to significant friction, heat and pressure forces during firing from a rifled barrel—such that there is a significant risk of material failure. Regardless, use of such significantly lighter weight composite material sabots, such as APFSDS, which could be fired at much higher muzzle velocities, to provide increased range, and target penetration—which is certainly desirable to enhance the performance of rifled weapons, such as 105 mm APFSDS and the 120 mm APFSDS.
Clearly there is a need in the art for a light weight, lower mass, composite material sabot, that can be fired from rifled gun tubes with greater velocity; but, which has the torsional/hoop strength to survive the forces created by the launch spin of a rifled gun tube; which are constructed such that there is no damage to the sabot's composite material due to the physical conditions to which it is exposed; and, which is constructed so as to reduce the spin, thereby reduce the hoop stresses.